Evacuated Glass Tube Solar Collectors

Evacuated glass Tube Collectors are the newest solar collector technology in South Africa. The technology used to manufacture this type of collector requires specialised machinery and equipment.

The great advantage of these tubes is their absorption of the sun’s infra-red rays which are able to pass through clouds. The inner tube is coated specially to absorb maximum solar heat and reflect the minimum. As for wind and low temperatures? Vacuum tubes are significantly less affected by these because of their insulating properties.

Evacuated Glass tube collectors heat the glycol which is in the copper tube and transfer this heat to the copper heat exchanger found in the aluminium manifold.The glass tube consists of an inner and outer glass tube sealed in a vacuum. The outer surface of the inner tube has a black copper metal coating used to absorb the infrared rays and the inner surface of the inner tube is silver mirror coated copper used to eliminate transmission (re-radiation).

Evacuated Glass Tube collectors can only be mounted vertically directly onto the roof or mounting frame which is mainly used for flat roof installations. A good quality evacuated glass tube collector should consist of the following:

58mm diameter glass tubes with a wall thickness of 2mm

Glycol filled Copper heat pipes

Aluminium reflector fins found in the glass tube

Copper heat exchanger found in the aluminium manifold

Stainless steel nuts and bolts for frame assembly

With the above materials used for the collector the optimal performance absorption will be +- 98% with an emission (re-radiation) of +- 2%.Hi Temp offer the above evacuated solar collector which is CE approved and SABS compliant.

There are 3 installation options we offer for the evacuated glass tube solar collector system.

Option 1:

Retrofit Pumped Split System using Photovoltaic Panel and 12 volt circulation pump – this is when the customers’ existing geyser is used and adapted to use solar.

The evacuated glass tube solar collector is mounted on the roof and connected to your existing Kwikot or equivalent geyser. The water is circulated through the flat plate solar collector using a 12 volt pump and photovoltaic (PV) panel to power the pump. As soon as there is sun on the PV panel the pump begins to circulate the geyser water through the flat plate solar collector. No timers are required. The existing heater element is used as a back-up should there be no or little sun for a few days continually.

The above system will cost from R8999 installed, including the Eskom homeowners rebate.

What Is Included?

Evacuated glass tube collector (size 20x 58mm diameter 1800mm long)

12 volt circulation pump

10 watt Photovoltaic solar panel

Non-return valve

5.5m copper tubing and lagging

Installation*

Option 2:

Retrofit Pumped Split System using 220 volt circulation pump and intelligent solar controller – this is also when the customers’ existing geyser is used and adapted to use solar.

The evacuated glass tube solar collector is mounted on the roof and connected to your existing Kwikot or equivalent geyser. The water is circulated through the flat plate solar collector using a 220 volt pump and an intelligent solar controller. The intelligent solar controller manages the entire geyser heating process. Sensor probes are used to monitor the geyser water temperature and evacuated glass tube solar collector temperature.

The existing heater element is also controlled and can be pre-set to various heating times throughout the day, as a back-up.

The above system will cost from R9999 installed, including the Eskom homeowners rebate.

What Is Included?

Evacuated glass tube collector (size 18 x 58mm diameter 1800mm long)

220 volt circulation pump

Intelligent Solar Controller Geyserwise MAX

Non-return Valve

5.5m copper tubing and lagging

Installation*

Option 3:

Thermosiphon Solar System: This is when the new solar geyser is mounted higher than the Evacuated glass tube solar collector and uses natural convection to circulate the water.

The Evacuated glass tube solar collector is mounted on the roof lower than the new solar geyser. The water is circulated through the Evacuated glass tube solar collector using natural convection. The water is circulated throughout the day providing there is sunlight on the Evacuated glass tube solar collectors. A backup heater element is present should there be little or no sun continually for a few days.

The above system will cost R13999*(150 litre solar geyser) or from R14999* (200 litre solar geyser) installed, including the homeowners rebate.